Apparatus for winding toroidal power transformers



March 8, 1966 A. A. HALAcsY APPARATUS FOR WINDING TOROIDAL POWER TRANSFORMERS 5 Sheetsf-Sheet 1 Original Filed July 13, 1961 INVENTOR. ANDREW A. HALACSY ATTORNEY March s, 1966 A. A. HALACSY 3,239,153

APPARATUS FOR WINDING TOROIDAL POWER TRANSFORMERS 5 Sheets-Sheet 2 Original Filed July 15, 1961 INVENTOR. ANDREW A. HALACSY Yfm la. M

ATTORNEY March 8, 1966 A. A. HALAcsY APPARATUS FOR WINDING TOROIDAL POWER TRANS'FORMERS 5 Sheets-Sheet 5 Original Filed July 15, 1961 FIG. 4

Fl G. 7 fw FIG. Il

am I\ INVENTOR. ANDREW A.HAl AcsY ATTORNEY March 8, 1966 A. A. HALAcsY 3,239,153

APPARATUS FOR WINDING TOROIDAL POWER TRANSFORMERS Original Filed July 13, 1961 5 Sheets-Sheet 4 1M sbl/we (24) 1M 22 M4 M ,ma M6 M\ l llll/ l 3 l FG. 5 l i JM INVENTOR. ANDREW A. HALACSY ATTORNEY March 8, 1966 A. A. HALAcsY 3,239,153

APPARATUS FOR WINDING TOROIDAL POWER TRANSFORMERS Original Filed July 13. 1961 5 Sheets-Sheet 5 FIGJOQ FIG. lOb

INVENTOR. ANDREW A. HALACSY ATTORNEY United States Patent O M 3,239,153 APPARATUS FR WINDING TOROIDAL POWER TRANSFORMERS Andrew A. Halacsy, Elizabeth, NJ., assignor to Federal Pacific Electric Company, a corporation of Delaware Original application July 13, 1961, Ser. No. 123,859, now

Patent No. 3,195,820, dated July 20, 1965. Divided and this application Feb. 2, 1965, Ser. No. 438,145

9 Claims. (Cl. 242-4) This application is a division of my application Serial No. 123,859 tiled July 13, 1961, entitled Method for Winding Toroidal Power Transformers, now Patent No. 3,195,820.

This invention relates to apparatus for winding toroidal power transformers for the distribution of electrical power. So-called pole transformers are an example of what is intended.

Transformers employing cores formed as wound coils of magnetic strip and of generally rectangular shape are commonly used for power distribution. Such transformers are high in electrical eiiiciency, but practical methods and apparatus have not been available for making toroidal windings on a toroidal core. Currently used transformers use a current-carrying or copper coil that is either pre-Wound or wound in situ on one leg of a wound core, and accordingly it has been necessary to form the core as a modified rectangle with at least one straight side for the copper coil. Such an arrangement is less eicient in operation and in utilization of copper and iron, and is heavier and bulkier than would be the case if the core were toroidal and had a toroidal conductive winding with a hole in the toroidal core of minimum diameter to accommodate the turns of the toroidal conductive winding.

Small toroidal-core devices having toroidal windings are used in computers and in communications devices; and somewhat larger toroidal devices have been used as variable-autotransformers. The apparatus for making such windings and the proportions of such devices are both unsuited to application in distribution transformers. Therefore, an object of this invention is in the provision of apparatus for winding toroidal primary and secondary current-carrying coils on a toroidal core in making a distribution power transformer.

Another object of this invention is the provision of apparatus capable of carrying out simply, economically, and easily, the basic teachings of the novel method described and claimed in my copending application Serial No. 123,859 tiled July 13, 1961 now Patent No. 3,195,820 issued July 20, 1965 of which this application is a division.

In one aspect of the invention there is provided apparatus for placing primary and secondary windings on a toroidal core for use as a distribution power transformer. The apparatus includes means for positioning the core with its central axis lying in a given plane, a shuttle about which is wound a length of wire which is ultimately to be placed on the core, means for rotating the core about an axis normal to the given plane, and means for passing the shuttle through the aperture in the core intermediate the rotations of the core.

For better understanding the invention, including the foregoing and certain additional objects and features of novelty, reference is made to the following detailed description of an illustrative embodiment thereof, which is shown in the accompanying drawings. In the drawings:

FIG. l is a plan View of the novel illustrative transformer winding apparatus;

FIG. 2 is a front elevation View of the apparatus of FIG. 1;

FIG. 3 is a right-hand end view of the apparatus of FIG. 1 with the shuttle conveyor omitted and other parts broken away in the interest of simplicity and clarity;

3,239,153 Patented Mar. 8, 1966 ICC FIG. 4 is an end view on an enlarged scale and in partial section taken along the line 4-4 of FIG. 2, additionally showing a supply of wire used in carrying out a particular method;

FIG. 5 is a plan view on an enlarged scale and in section taken along the line 5-5 of FIG. 3 showing one stage in the winding operation;

FIG. 6 is a view similar to FIG. 5 at a subsequent stage in the winding operation;

FIG. 7 is a cross-section of a portion of the wire placing apparatus taken along the line 7-7 of FIG, 5;

FIG. 8 is a cross-section of the shuttle-supporting apparatus taken along the line 8 8 of FIG. 1, shown on an enlarged scale, showing the shuttle in place;

FIG. 9 is a cross-section of the shuttle-supporting apparatus taken along the line 9-9 of FIG. 1 on an enlarged scale;

FIGS. 10a to 101' are a diagrammatic presentation of various phases in the novel winding method; and

FIG. l1 is a diagrammatic View of a core and its supporting rollers, representing the progression of turns made by gradual rotation of the transformer core about its central axis.

Referring to the drawings, the toroidal power transformer being wound comprises a core 20 on which one or more turns of wire 22 are shown. Transformers of this type, having other new and useful features, are described in full in my co-pending U.S. applications Ser. Nos. 47,200, now Patent No. 3,201,734 and 47,201 which are assigned to the assignee of this application. An illustrative size of transformer which may be fabricated in accordance with features of this invention has a wound core of silicon steel weighing 787 pounds. The core has an inner diameter of 81/2 inches, an outer diameter of 211/2 inches, and a height of 13% inches. During the manufacturing operation, some 39,260 inches of .108 inch diameter insulated copper wire are applied in discrete lengths as the primary and secondary windings, the complete transformer having an overall weight of 890 pounds exclusive of mounting, protective and cooling structures.

. The length of wire would, of course, be divided into the primary and secondary windings as required by the transformer design.

The length and cross-section of wire in a particular winding is determined by the engineering design of the transformer. The method of winding the wire on a core will first be described with reference to FIGS. 10a to 10i. Once the length of wire required for particular winding has been determined, the wire 22 is wound in a configuration capable of being passed through the aperture in the core as for example on a shuttle 24 which, when fully loaded, is able to pass through the aperture of the core with suicient clearance for previously positioned wires. The free end of the wire 22 is secured to the core as by taping (FIG. 10a) and the shuttle 24 is then fed through the aperture or window in the core 20 (FIG. 10b). The wire is drawn taut against the core by drawing the shuttle away from the core 20 (FIG. 10c). Core 20 is then rotated through a half-revolution (FIGS. 10d and 10e). After completion of one lengthwise stroke of the shuttle and a rotation of the core as thus far described, it will be recognized that a full turn has been wound about the core. The wire that initially was angled away from the lower side of the shuttle as illustrated in FIG. 10a assumes a position angled away from the upper side of the shuttle in the illustration of FIG. 10e. A full turn of wire has thus been wound around the core, and a half-turn of wire has been unwound from the shuttle. Shuttle 24 is reciprocated once again, traveling through the core as shown (FIGS. 103c and 10g). Core 20 is rotated through a second halfrevolution (FIGS. 10h and 10i), thereby completing a second turn of wire about the core and restoring the parts to the condition shown in FIG. a. The second stroke of the shuttle (FIGS. 10]c and g) followed by the second 180 rotation of the core thus winds a second turn about the core and unwinds a second half-turn of wire from the shuttle. In the preferred embodiment illustrated, the core is rotated through a half-turn and the shuttle reciprocated in alternate feeding and rotating steps until the entire length of wire carried by the shuttle has been wound upon the core. The core is also gradually rotated about its central axis between the strokes of the shuttle 24 so that the successive turns of wire 22 are placed upon the core 20 in the desired relation, whether spaced apart, abutting or overlapping, as may be required iin the transformer design.

The length of the shuttle 24 is such that one half of a loop of wire about the shuttle is, to a close approximation, equal to a full turn of the winding on the core. This may not be exact and consequently it may be necessary to reverse the shuttle lengthwise i.e., turn the shuttle end-for-end, after a number of strokes of reciprocation in order to keep a reasonable length of wire between the shuttle and the core. Apart from such occasional endfor-end reversals, the only motion of the shuttle is one of repeated lengthwise reciprocation.

An apparatus capable of carrying out the steps of the aforedescribed method is shown in FIGS. 1-9 and 11. The apparatus includes a lower or base support 26 for the core 2t). Support 26 comprises a pair of opposed side frames 28, 30 which are adjustably secured to a rotatable platform 32. Core supporting rollers 34 are mounted on shafts 36 which extend in bearings 38 affixed to the walls 28, 30. Bearings 38 are adjustably carried in slots 39 in frames 2S, 30 so that their position may be adjusted radially of the center of the core to compensate for various core sizes without changing the position of the center hole or window of the core. One of the shafts 36 is provided with a handle 40 whose function will be discussed in greater detail in connection with the operation of the apparatus. The separation between side frames or walls 28, 30 is adjustable so that the support 26 may be adjusted to correspond to various core sizes, with clearance for the windings.

Platform 32. is rotatably supported on table 42 by bearings 44. Upper support 46 is carried by posts 48 secured to the table 42 exteriorly of the rotatable platform 32. Upper support 46 is removably held on the posts 48 and is removed when loading and unloading the apparatus.

Rotatable core support 52 is pivotally mounted at the center of the upper support 46 upon a hollow shaft 54 (se-e FIG. 4). Shaft 54 is xed to bearing collar 56 that rests on bracket 46 to carry core support 52. Shaft 54 has a slot 54a in line with a like slot (not shown) in bearing 56, so that one position of shaft 54 lines up the slots in the shaft and in the bearing collar. The slot in bearing 56 is contiguous with a slot (not shown) formed in the bracket 46. A slotted shuttle carrier 55 is affixed to the upper end of shaft 54. The slot 55a in shuttle carrier 55 is in line with slot 54a in shaft 54. In the position shown in FIG. 1 the various slots of the fixed and rotatable portion of the apparatus are aligned to form a passageway 57 from the exterior of the apparatus to the center of shaft S4.

The core support 52 includes a pair of channel members 58 which are secured to a collar 60 carried by shaft 54 with a slot in the collar (not shown) aligned with the slot 54a in the shaft. The channel members S8 are oppositely disposed about shaft 54 with their longitudinal axis parallel to the slot 54a in the shaft. Opposed core support rollers 62 are affixed to channel members 58, and are adjustable therealong to allow for various core widths. The rollers 62 are removably secured by bolts 64 to the channel members 58 so that a wire 22 may be passed between the members 5'8 into the center bore of the shaft 54a.

Platform 32 is rotated by means of main shaft 66, which depends beneath the platform 42 and is coaxial with hollow shaft 54. Synchronized rotation of upper core support 52 and platform 42 is accomplished by the following mechanism, best shown in FIG. 3. External drive shaft 68 is notably supported at its upper end from an extension 70 (FIG. l) of bracket 46 and at its lower end by a bracket 71 extending from platform 42. Sprocket 72 aiiixed to the main shaft 66, is connected to sprocket 74 on drive shaft 68 by a chain 76. Sprocket 78 on shaft 54 has a slot (not shown) contiguous with and connecting to slot 54a in the shaft and is connected to the sprocket 80 on drive shaft 68 by chain 82. Chain 82 is provided with removable links so that it may be temporarily disassembled to allow wire 22 to be positioned in the bore of shaft 54. Drive shaft 68 is rotated by the drive gear arrangement 84 and handle 86.

Where a short length of wire is involved, Wire 22 may be wound upon a single shuttle 24. Referring to FIGS. 1 and 8, a typical shuttle 24 comprises a pair of opposed longitudinally extending side plates 88 which are secured to a number of spacer portions 90 by suitable means. The width and height of the shuttle are selected so that the shuttle may pass through the window in the core during the winding operation. The length of the shuttle and spacers may be varied to accommodate different lengths of wire as required by the transformer being wound. In the preferred embodiment, the length of a turn of wire about the shuttle is at least equal to twice the length of the turn wound about the core.

Where the amount of wire for a winding to be placed upon the core is greater than that which can be accommodated by a single shuttle within the previously described restrictions, it is of special advantage to employ two shuttles to apply the continuous length of wire. The wire is wound upon two shuttles starting from the free ends of the wire and winding it about the shuttles toward its midpoint. The manner in which the two-shuttle method functions as distinguished from the previously described single shuttle method will be discussed in detail later. Roller conveyors 92 are provided to assist in carrying the winding shuttle 24 toward and away from the core 20. The shuttle is moved by suitable means, as by hand, toward, through and away from the core. In the apparatus shown in the drawing, the conveyors 92 comprises a channel frame 94 within which a plurality of rollers 96 are journaled at their ends. The rollers 96 are notched at 9S to provide clearance for the shuttle 24 (FIG. 8). It is contemplated that power means may be used to move the shuttle along the conveyor 92, either by powering the conveyor or by providing external means.

Wire snubblers 100, which form the wire 22 against the core as it is wound, are pivotally mounted on the posts 48 (see FIG. 7). These snubbers are constrained to a desired position relative to the core 20 by torsion springs 102. Snubber shaft 104 is slidable within housing 106 against which the torsion spring 102 reacts. Adjustable stops 108 on shaft 104 are provided to control the extension of the shaft 104 and roller 110 which is carried at the end of the shaft 104. The shaft 104 is maintained in its extended position by compression spring 112. The periphery of each roller 110 is wide enough to contact several wires on the core and to roll them against the core. The roller may be of steel but is advantageously fabricated from slightly resilient material as for example nylon or Teflon which are relatively rigid plastic materials.

Reference will now be made to a typical cycle of operation of the present machine, to facilitate a more thorough understanding of the invention. In carrying out the winding of a core 20 with either a single shuttle 24 or with a double shuttle 24a and 2412, as will be later 1in certain-transformer congurations. half'the circumference of the shuttle is substantially equal 'to' the length of a single turn on the core, it may be ad- .vantageons to increase the length of the shuttle to reduce .core (FIG. a).

.side ofthe core (FIG. 10c).

:its vertical axis 180.

additional wire. the shuttle approximates two turns around the core, or

described, a core is loaded into the support frame 26.

To facilitate this, one of the rollers 34 and its shaft 36 may be removed, and restored after the core is in place. The core is placed in the apparatus between the side plates 28, 30. The upper core support 46 is placed on lthe posts 48 with the rollers 62 disposed on opposite sides of the core. Chain 82 is reconnected so that the ro- ,tation of the upper and lower core supports 26 and 46 through shafts 54 and 66, which is perpendicular to the given plane. The upper and lower supports also center the core 20 relative to the vertical axis.

In carrying out the aforedescribed single shuttle method, a predetermined length of wire equivalent to the length of a particular ,number of turns .of a winding, is wound upon the shuttle 24 (which may be two Or more "shuttles joinedv end-to-end to achieve the desired wire capacity). i The particular number of turns may be equivalent to a complete Wirlding or a portion thereof since lseveral sets of ywindings may be connected in parallel While, preferably,

the number of bends necessarily made in the wire in preliminarily winding it about the shuttle.

The shuttle 24 is placed on a conveyor as, for example, roller conveyor 92, and the free end of the wire 22 is -temporarily secured, as by taping, to the exterior of the The end may be connected to a terrninal or to another winding later. The shuttle is passed through the core aperture (FIG. 10b) and to the opposite The core is rotated about The rotation is produced by the driveA gears 84 through shaft 68. Shuttle 24 is passed .back through the core drawing the wire 22 with it.

It is not necessary for the shuttle to be turned end-for-end yto either take up the slack in the wire or to pay out In that event the circumference of oneturn about thecore equals approximately the length or half the circumference of the shuttle. However, turning the shuttle end-for-end will either take up the Wire or lengthen it as required. The entire wound length of wire is transferred from the shuttle to theA core by suc- .,cessive rotations of the core and passes of the shuttle.

V Referring to FIGS. 5 and 6, the snubbers 100 form the Wire 22 against the core 20 as the core is rotated. Effecltvely, the wire is passed fronrone snubber to the next lby the rotation of the core.

The snubbers maintain the last Wound turns in position on the core as the shuttle is reciprocated. The torsion springs 102 (FIG. 7) swing each snubber roller 11G into the path of the core and the compression springs 112 force the roller against the wire and the wire against the core.

It is advantageous for the core to be rotated step-Wise about its central axis between reciprocations of the shuttle so that succeeding turns of the wire may be placed on the core adjacent the previously wound turn. This is accomplished by means of one of the supporting rollers 34 which frictionally engages the core as can be seen in FIG. 11. peripheral distance equivalent to the widthof the wire. This movement may occur either intermediate the rotation of the core about the vertical axis of the apparatus or simultaneously therewith. The reciprocating movements of the shuttle intermediate the step-wise 180 rotation of the core (FIGS. 10a to z') are continued with the wire being layed against the core in a desired conguration, until the length of wire wound on the shuttle The core is revolved about its central axis a v has been exhausted. The end of the wire is then ternporarily taped to the core. Subsequent windings may be positioned -on the core by repetition of the singleshuttle method previously outlined above and may be connected to either the previously wound turns or to a terminal. The wound core is removed from the apparatus by reversing the loading procedure described above.

In some circumstances, the length of wire to be wound for a particular winding must be in one piece and is such that it is most advantageous to employ two shuttles. In the two-shuttle method, the length of wire is wound upon two shuttles starting from the free ends of the wire and winding toward the center thereof. The core is positioned as before and the rst or A shuttle 24a is positioned in carrier (FIG. 4) on shaft 54. The slots in the carrier 5S, shaft 54, collar 56, sprocket 78, yoke support bushing 60, are aligned and a core support roller 62 and sprocket chain 82 are removed and the wire. 22 is led through the slots. The sprocket chain 82 and the core support roller 62 are then replaced. The B or second shuttle (not shown) is placed on the conveyor 92 and passed through the core' aperture. vThe wire 22 is then taped to the core Ztl Where it vpasses through the aperture and the winding operation proceeds as previously described for the single. shuttle method. The A shuttle 24a, carrier 55, support 52, and core 20 rotate together therefore no twisting of the wire occurs between the shuttle and the core. When the B shuttle is exhausted, the A shuttle is then employed to nish the winding. The shuttle is removed from the carrier 55 by passing the wire through the various aligned slotted members once the sprocket chain 76 and core support roller 62 have been removed. If the B shuttle has been wound onto the core with a clockwise rotation of the core then the A shuttle is wound on the core in a counter-clockwise direction so that the turns remain in their proper relative position on the core. The core is rotated about its central axis during the winding so that subsequent turns may be placed next to one another in a spiral, serial manner. When the B shuttle has been emptied and the free end taped to the core, the taped midpoint is returned to the starting position and the core rotated in the reverse direction for the A shuttle.

The method, and apparatus for carrying out the method herein described, allow, for the rst time, the production of distribution power transformers having toroidal cores.

Although several embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.

What I claim is:

1. An apparatus for winding a wire on a core having an aperture along its central axis for use as a power transformer comprising the combination of means for supporting said core with its central axis lying in a given plane, a shuttle adapted to have a length of wire wound thereon, means for rotating said core about an axis normal to said given plane, and means for passing said shuttle through said aperture in said core substantially along said central axis intermediate the rotations of said core.

2. An apparatus for winding a wire on a core having an aperture along its central axis for use as a power transformer comprising the combination of means for supporting said core with its central axis lying in a given plane, a shuttle adapted to have a length of wire of a given diameter wound thereon, means for rotating said core about an axis normal to said given plane, means for passing said shuttle through said aperture in said core substantially along said central axis intermediate the rotations of said core, and means for angularly rotating said core about said central axis a distance equal to said given diameter of the wire.

3. An apparatus for winding a wire on a toroidal core having a central axis passing through the aperture in said core for use as a power transformer comprising the combination of means for supporting said core with its central axis in a given plane, said support means including a pair of opposed side frames, a plurality of support rollers mounted between said side frames and arranged to frictionally engage the periphery of said core, a shuttle adapted to have a length of wire wound thereon, means for step-wise rotating said core and support means 180 about an axis normal to said given plane, means for reciprocatingly and sequentially passing said shuttle through said core along said central axis intermediate the step-wise rotations of said core whereby a wire contained on said shuttle may be wound upon said core thus forming a winding thereon.

4. An apparatus for winding a wire on a toroidal core having a central axis to form a power transformer comprising the combination of means for supporting said core with its central axis in a given plane, a shuttle adapted to have a length of wire of a given diameter wound thereon, means for step-wise rotating said core 180 about an axis normal to said given plane including a rotatable carrier for said support means, means for rotating said carrier, means for reciprocatingly feeding said shuttle through said core along said central axis intermediate the step-wise rotations of said core, and means for Irotating said core about its central axis a distance equal to the diameter of the wire being Wound thereon.

5. An apparatus for winding a wire on a toroidal core having a central axis for use as a power transformer comprising the combination of means for supporting said core with its central axis lying in a given plane, a pair of shuttles adapted to receive a length of wire wound thereon from the ends of the wire inwardly, means for step-wise rotating said core 180 about an axis normal to said given plane, means supporting one of said shuttles for simultaneous, selective rotation with said core to prevent relative rotation between the rotated shuttle and the core, means for passing the shuttles through said core substantially along the central axis of said core intermediate the step-wise rotation of said core to thereby wind said wire upon said core.

6. An apparatus for winding a wire on a toroidal core having a central axis for use as a power transformer comprising the combination of a fixed frame, a platform rotatable relative to said frame, a pair of side plates mounted on said platform, a plurality of rollers arrayed between said side plate and arranged to engage the periphery of said core whereby said core is supported with its central axis in a given plane and said core is rotatable about said axis, an upper support for said core mounted for relative rotation on said xed frame, and means synchronizing the rotation of said platform and said upper support.

7. An apparatus for winding a wire on a toroidal core having a central axis for use as a power transformer comprising the combination of a fixed frame, a platform rotatable relative to said frame, a pair of side plates mounted on said platform, a plurality of radially arrayed rollers carried between said side plate and arranged to engage the periphery of said core whereby said core is supported with its central axis in a given plane, an upper support for said core mounted for relative rotation on said xed frame, a shuttle support carried by said upper support and rotatable therewith, and means synchronizing the rotation of said lower platform and said support.

S. An apparatus for winding wire on a toroidal core having a central axis passing through the aperture in said core for use as a power transformer comprising the combination of means for supporting said core with its central axis in a given plane, a shuttle adapted to have a length of wire wound thereon, means for step-wise rotating said core about an axis normal to said given plane, means for passing said shuttle through said core substantially along its central axis in one direction intermediate the movement of said core and returning said shuttle to its original position subsequent to the next rotation of said core, means for forming said wire against said core, and means for rotating said core about said central axis a distance equal to the diameter of the wire contained on said shuttle.

9. An apparatus for winding wire on a core having a central axial aperture to form a power transformer comprising the combination of a xed table, a rotatable platform mounted on said iixed table, a drive gear secured to said platform, a pair of side plates mounted on said platform, a plurality of rollers arrayed between said side plates and arranged to engage the periphery of said core whereby said core is supported with its central axis in a given plane, means for driving said rollers whereby said core may be selectively rotated about its central axis, vertical posts secured to said table, a slotted X-shaped bracket removably affixed to said posts, a slotted collar mounted at the midpoint of said bracket, a slotted shaft rotatably carried by said collar, a slotted sprocket aixed to said shaft, an upper yoke-shaped core support affixed to one end of said shaft, a slotted shuttle carrier affixed to the other end of said shaft, drive means engaging said sprocket and said drive gear for simultaneous step-wise rotation of said upper support and said platform, a shuttle adapted to have a length of wire wound thereon, a pair of opposedly mounted roller conveyors adjacent the opposite sides of said iixed table for receiving said shuttle, and means for reciprocatingly feeding said shuttle from one conveyor to the other and through said aperture in said core intermediate the step-wise rotation of said core in said given plane and about its central axis.

References Cited by the Examiner UNITED STATES PATENTS 2,102,692 12/1937 Franz 242-4 2,467,643 4/1949 Wirth 242-4 2,820,598 1/1958 Aveni 242-4 2,857,112 10/1958 Tibbetts 242-4 3,128,955 4/1964 Stutz 242-4 FOREIGN PATENTS 857,050 12/1960 Great Britain.

MERVIN STEIN, Primary Examiner.

B. S, TAYLOR, Assistant Examiner, 

1. AN APPARATUS FOR WINDING A WIRE ON A CORE HAVING AN APERTURE ALONG ITS CENTRAL AXIS FOR USE AS A POWER TRANSFORMER COMPRISING THE COMBINATION OF MEANS FOR SUPPORTING SAID CORE WITH ITS CENTRAL AXIS LYING IN A GIVEN PLANE, A SHUTTLE ADAPTED TO HAVE A LENGTH OF WIRE WOUND THEREON, MEANS FOR ROTATING SAID CORE ABOUT AN AXIS NORMAL TO SAID GIVEN PLANE, AND MEANS FOR PASSING SAID SHUTTLE THROUGH SAID APERTURE IN SAID CORE SUBSTANTIALLY ALONG SAID CENTRAL AXIS INTERMEDIATE THE ROTATIONS OF SAID CORE. 